Paul hardegen



No. 753,391. PATENTBD MAB. 1,1904. P. HARDBGEN. CASING FOR TELEPHONES ORMICROPHONES.

APPLIdATIOH FILED SE21. 3, 1902.

N0 MODEL.

Patented March 1, 1904.

.UNITED STATES PATE T OFFICE.

PAUL .HARDEGEN, OF BERLIN, GERMANY.

CASING Fol? TELEPHONES OR MICROPHONES.

SPECIFICATION forming part of Letters Patent No. 753,391, dated March 1,1904.

Application filed September 3, 1902. Serial No. 122,000. (No model.)

To all whom it may concern:

Be it known that I, PAUL HARDEGEN, manufacturer, a subject of the Kingof Prussia, German Emperor, residing at No. 5/6 Elisabeth- Ufer, Berlin,in the Kingdom of Prussia, Ger: man Empire, have invented new and usefulImprovements in Casings for Telephones and Microphones,of which thefollowing is a specification.

My invention relates to improvements in casings for telephones andmicrophones,whereby by the latter are protected against atmosphericalinfluences; and the objects of my improvement are, first, to provide aprotective bellshaped casing of steel, iron, and the like; second, toprovide a core of steel, iron, and the like and to place it in magneticconnection with said casing, soas to form therewith a bipolar magnetunder the influence of an electrical current; third, to provide a coilon said core while being insulated therefrom and from said casing;fourth, to provide a protective cover having either a large centralaperture or a plurality of line slits and arranged for holding avibrating diaphragm Within said casing; fifth, to provide twosemicircular springs on said cover, which are preferably in theirmiddles secured to the cover and leave between their free ends spaces,they being arranged for grasping the external edge of the casing, and,sixth, to provide a pin on said casing for engaging the spaces betweenthe ends of said springs, and thereby preventing the cover from turning.I attain these objects by the arrangement illustrated in theaccompanying drawings, in which Figure l is a side view of a microphoneor combination of a telephone with a microphone, both being constructedin accordance with my invention. Fig. 2 is a rear view of the telephone.Fig. 3 is a front view of the cover of the same. Fig. 3 is a top view ofthe same. Fig. 4 is a vertical longitudinal section of the telephone onthe line A Bin Fig. 2. Fig. 5 is a rear view of the two springs arrangedfor being secured to the rear side of the cover, and Fig. 6 is a sideview of the casing alone to show its pin (Z.

Similar letters of reference refer to similar parts throughout theseveral views.

The protective casing a of the telephone is bell-shaped, preferably inthe shape shown, and pressed from sheet of steel, iron, and the like, soas to be capable of forming with the core f, of steel, iron, and thelike, a bipolar magnet under the influence of an electric current. Thecasing a is mounted on the core f and magnetically connected therewith.For securing these two parts a nut g is employed. On the core f withinthe casing a a coil c' is mounted, which is insulated both from the coreand from the casing. Its two wires Z Z in a usual manner lead to a cable0, contained in the handle a. For protecting also the vibratingdiaphragm m from the atmospherical influences in the simplest mannerwithout the use of any thread a cover I), having a raised edge 7*, (seeFig. 3,) is employed, which is provided with two semicircular springs ca, the middles of which are aflixed to the cover 6 by means of rivets wm or other suitable means. The springs c c are preferably round insection, as is shown in Fig. 45, so as to be capable of easily grippingover and snapping behind the edge of the casing a. (See Figs. 1, 2, and4.) In order toprevent the cover 5 from turning on the casing a, thelatter is provided with a pin cl, (see Fig. 6,) which engages the space6 between two neighboring ends of the springs c 0. Where it is sopreferred, a packing-ring may be arranged on the inside of the cover 6along its edge 1*. It will be seen that for closing the casing a allthat is requireiis to simply put the cover 6 on the edge of the casing,when its springs c 0 will yield, grip over, and snap behind the edge ofthe casing. Then the cover 6 will be held securely. It is preferable toso arrange the two semicircular springs 0 c that their free ends arekept at a certain distance from the cover, as is shown in Fig. 1, sothat they are enabled to draw the cover and its packing-ring moretightly to the edge of the casing.

The cover 6 is arranged for holding a V1 brating diaphragm m, which maybe kept at a certain distance from the cover by a more or less elasticring 79. When the cover I) is put on the casing a, the vibratingdiaphragm m will be secured between the edge of the cover and that ofthe casing, and thus be put into contact with the second pole of themagnet.

The cover 6 is preferably provided with a plurality of fine slits h,(see Fig. 3,) arranged in concentrical circles or in any suitableuniform manner for allowing of the verberations caused by the voicereaching the vibrating diaphragm m. Where it is so preferred, however,the cover I) may have a large central aperture in place of the slits h.

The microphone is similarly arranged as the telephone as far as thecasing and the cover are concerned. The corresponding parts are denotedby the same letters, with the exception that the index has been added.

- -Having now described my invention, that what I wish to secure byLetters Patent of the United States is- The combination with a core ofsteel, iron and the like, of a bell-shaped casing of steel, iron and thelike capable of forming with said core a bipolar electromagnet, aninsulated coil mounted on said core within said casing and placed in anelectrical circuit, a cover for said casing, a vibrating diaphragm heldby said cover within said casing near said core, said cover having aplurality of apertures for allowing of the verberations of the voicereaching said diaphragm, two semicircular springs secured to said coverfor grasping the edge of said casing, and a pin on said casing forengaging between the free ends of said springs and thereby preventingsaid cover from turning, substantially as set forth.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

PAUL HARDEGEN.

Witnesses WOLDEMAR HAUPT, WILLIAM MAYNER.

